Vascular Access Port (VAP) Usage in Large Animal Species

Intravascular catheterization access for injection and sampling is one of the most common experimental surgical procedures. The vascular access port (VAP) was developed as an alternative to externalization of catheters. A VAP typically is implanted subcutaneously, with an attached catheter that is tunneled to a blood vessel for chronic catheterization. Catheters and ports have been designed to reduce the problems of occlusion, venous thrombosis, and infection. Key issues involve the use of meticulous aseptic technique for implantation of the devices and a "locking" solution that prevents clotting and retention of residues within the catheter. There are species-specific differences to be considered when planning the surgical implantation and maintenance of these devices. This manuscript reviews the procedures that have been used in the implantation of VAPs in large animal species and makes recommendations for procedures that will decrease complication rates associated with long-term catheterization.